Abstract:

An article produced using, among other techniques, free-form fabrication
having a binder matrix and particles can be supported during a
temperature processing, such as burn-out of the binder matrix, with a
support composition to maintain geometry and/or alleviate changes in
geometry of the article. The support composition can take a variety of
forms such as foams, two phase materials, plastic powders, carbon
powders, etc. The support material is sacrificed during the thermal
processing, such as through decomposition. Such a decomposition can occur
when the support composition evolves into a carbonaceous structure. The
support composition can also oxidize to a gas, melt, or vaporize, among
other types of sacrificial action.

Claims:

1. An apparatus comprising:a ceramic mold article capable of being
thermally processed from a pre-fired shaped to a fired-shape to produce a
fired ceramic mold; anda sacrificial structural material coupled with the
ceramic mold article to stabilize the orientation of the ceramic mold
article, the sacrificial material dispersible when the ceramic mold
article is thermally processed.

2. The apparatus of claim 1, wherein the ceramic mold article is a green
ceramic mold prior to being thermally processed from the pre-fired shape
to the fired-shape, the green ceramic mold having a binder capable of
being burned out when the ceramic mold article is thermally processed.

3. The apparatus of claim 2, wherein the sacrificial structural material
is a foam.

4. The apparatus of claim 3, wherein the foam can be at least one of
insulating construction foam and isocyanate packing foam.

5. The apparatus of claim 2, wherein the sacrificial structural material
is capable of evolving into a rigid structure when the green ceramic mold
is thermally processed.

6. The apparatus of claim 2, wherein the sacrificial material can be one
of at least two phase materials, plastic powder, and carbon powder.

7. The apparatus of claim 2, wherein the sacrificial material is a
non-porous filler.

8. The apparatus of claim 1, wherein the ceramic mold article is an
investment casting mold for making a gas turbine engine airfoil member
upon being thermally processed to form the fired ceramic mold.

9. An apparatus comprising:a free-form fabricated mold having a binder
matrix capable of being burned out to form a fired ceramic mold; anda
supporting material coupled with and at least partially removable from
the free-form fabricated mold prior to producing a completed fired
ceramic mold, the supporting material structured to encourage the
free-form fabricated mold to maintain its shape at least during some
portion between the starting temperature and processed temperature.

10. The apparatus of claim 9, which further includes a furnace capable of
elevating the temperature of the free-form fabricated mold from a
starting temperature to a processed temperature to at least burn out the
binder matrix,

11. The apparatus of claim 9, wherein the mold includes a core and is
structured to form a gas turbine airfoil shape when used in an investment
casting process.

12. The apparatus of claim 9, wherein the free-form fabricated mold
includes a core and a shell, the supporting material disposed between a
portion of the core and a portion of the shell.

13. The apparatus of claim 11, wherein at least a portion of the
supporting material is oxidized to gas between the starting temperature
and processed temperature.

14. The apparatus of claim 11, wherein the supporting material changes
phase between the starting temperature and processed temperature.

15. The apparatus of claim 11, wherein the supporting material becomes a
rigid structure during some portion between the starting temperature and
processed temperature.

16. An apparatus comprising:a shaped mold article having a ceramic
particle and binder matrix composition, the shaped mold article operable
to be processed from a first state to the second state, the second state
characterized by a loss of at least a portion of the binder matrix;
andmeans for sacrificially supporting the shaped mold article during
processing from the first state to the second state.

17. A method comprising:forming a ceramic article having ceramic
particles;filling a space in the ceramic article with a sacrificial
support material;subjecting the ceramic article to a temperature process
for hardening the ceramic article; andremoving the sacrificial support
material during the temperature process.

18. The method of claim 17, wherein the forming includes constructing a
green ceramic article having a binder matrix and the ceramic particles,
and wherein the subjecting includes burning out the binder matrix and
sintering the ceramic particles.

19. The method of claim 17, which further includes supporting the ceramic
article during the temperature process, the supporting occurring during
at least a portion of the removing.

20. The method of claim 19, wherein the decomposing includes passing a
mass out of the ceramic article during the subjecting.

[0002]The present invention generally relates to fired articles such as
molds, and more particularly, but not exclusively, to supports for the
fired articles.

BACKGROUND

[0003]Providing support for articles capable of being fired or heated
during a temperature processing period remains an area of interest. One
non-limiting example of such articles include green ceramic articles
initially having a shape formed of a binder matrix and ceramic particles
where, during a thermal processing, the binder matrix is eliminated and
the ceramic particles are fused. Some existing systems have various
shortcomings relative to certain applications. Accordingly, there remains
a need for further contributions in this area of technology.

SUMMARY

[0004]One embodiment of the present invention is a unique support of an
article capable of being fired. Other embodiments include apparatuses,
systems, devices, hardware, methods, and combinations for supporting an
article during a firing process to minimize a change in geometry of the
article. Further embodiments, forms, features, aspects, benefits, and
advantages of the present application shall become apparent from the
description and figures provided herewith.

BRIEF DESCRIPTION OF THE FIGURES

[0005]FIG. 1 depicts one embodiment of an article.

[0006]FIG. 2 depicts one embodiment of an article coupled with a support
composition.

[0007]FIG. 3 depicts one view of an article coupled with a support
composition.

[0008]FIG. 4 depicts an embodiment of a gas turbine engine component.

[0009]FIG. 5 depicts an embodiment of a furnace or oven.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[0010]For the purposes of promoting an understanding of the principles of
the invention, reference will now be made to the embodiments illustrated
in the drawings and specific language will be used to describe the same.
It will nevertheless be understood that no limitation of the scope of the
invention is thereby intended. Any alterations and further modifications
in the described embodiments, and any further applications of the
principles of the invention as described herein are contemplated as would
normally occur to one skilled in the art to which the invention relates.

[0011]With reference to FIG. 1 and following figures, an article 50 will
be described that can be manufactured and processed for use as an
investment casting mold. In some forms the investment casting mold can be
used to produce aircraft gas turbine engine components such as, but not
limited to, blades and/or vanes an example of which is shown as reference
numeral 64 in FIG. 4. As used herein, the term "aircraft" includes, but
is not limited to, helicopters, airplanes, unmanned space vehicles, fixed
wing vehicles, variable wing vehicles, rotary wing vehicles, unmanned
combat aerial vehicles, tailless aircraft, hover crafts, and other
airborne and/or extraterrestrial (spacecraft) vehicles. Further, the
present inventions are contemplated for utilization in other applications
that may not be coupled with an aircraft such as, for example, industrial
applications, power generation, pumping sets, naval propulsion, weapon
systems, security systems, perimeter defense/security systems, and the
like known to one of ordinary skill in the art.

[0012]The article 50 can be produced using a variety of techniques,
including but not limited to free-form fabrication techniques. To set
forth just one non-limiting example, the article 50 can be produced using
virtual pattern casting. In one embodiment the article 50 can be formed
of a binder mixture, such as photoactive polymeric resin, and particles,
such as ceramic particles. In other forms the article 50 can be
substantially ceramic and in others can be made using other types or
forms of constituents.

[0013]The article 50 can be processed in an environment where the
temperature of the article is increased over time. For example, the
article 50 can be placed in a furnace or oven 62 (shown in FIG. 5) which
provides the energy required to raise the temperature of the article. In
the embodiments of the article 50 having the binder matrix this process
can include at least two phases, which may or may not be entirely
distinct from each other. In the first phase, sometimes called the
burn-out, the binder matrix at least partially leaves the article 50
causing it to shrink in size in at least one dimension. The term
"burn-out" refers to any process by which the binder matrix at least
partially leaves the article 50. In some applications the binder matrix
is removed via a pyrolosis process but other types of processes are also
contemplated herein. During the burn-out the article 50 can become
relatively weakened, such as through softening, which can lead to changes
in shape in the article 50. During the second phase, which typically
occurs at higher temperatures relative to the burn-out, the particles can
be bonded together thus forming a hardened article. In some embodiments
the particles can be bonded by sintering. The hardened article can be
used as a mold for investment casting as mentioned above. The thermal
processing can take the form of a time dependent temperature profile that
may or may not include temperature holds at certain temperature levels.
Any variety of forms of thermal processing are contemplated herein.

[0014]In the illustrative embodiment the article 50 includes a mold having
a shell 52 and a core 54. In other embodiments, however, the article 50
may have a mold different than that of the illustrative embodiment. In
some embodiments the article 50 can include a shell having relatively
thin walls. In still other embodiments, the article 50 can include one or
more passageways formed within the article to allow for passage of a
molten metal. The passageways can be formed between portions of the
shell, mold, or both, or any other suitable structure. The passageway(s),
furthermore, can include one or more bends or turns according to the
needs of a given application. In still other embodiments, the mold can
include numerous details that together form part of an engineered
article. To set forth just one non-limiting example, the mold can be used
in some applications to produce a gas turbine engine blade having
internal cooling passages.

[0015]Turning now to FIG. 2, the article 50 can be coupled with a support
composition 56 which can be used to support the article 50, or portions
of the article 50, during at least some portions of the temperature
processing discussed above. To set forth a non-limiting example of the
article 50 that includes the binder matrix, the support composition 56
can be used to stabilize the geometry of the article 50 as the
temperature processing softens the article 50 and the binder matrix at
least partially leaves the article 50. In some forms the support
composition 56 can be used within the article 50, such as between the
shell 52 and the core 54, among other possible locations. To set forth
just a few non-limiting examples, the support composition 56 can be used
to maintain the relative spacing of walls of a passageway, or maintain
the relative shape of the article 50 or at least portions of the article
50. In some applications the support composition 56 can be used to
prevent the collapse of a passageway or the distortions that may be
caused by gravity or other forces acting upon the article 50 during at
least some portion of a thermal processing.

[0016]The support composition 56 can be conveyed to locations within the
article 50 by actions that include, but are not limited to, pouring and
injecting. For example, the support composition 56 can have a relatively
liquid like properties which allows it to be poured on or into the
article 50. In other forms the support composition 56 can be injected
into or on the support composition 56. In one form the support
composition 56 can originate from a relatively pressurized container from
which it can be selectively dispensed and coupled with the article 50.
Other actions that provide for the support composition 56 to be conveyed
to the article 50 are also contemplated herein. Non-limiting examples of
the support composition 56 are provided below.

[0017]The support composition 56 can be made of a foam material that can
have an open cell construction. Some forms of the foam material can also
have a closed cell construction. Examples of foam materials include, but
are not limited to, insulating construction foam or isocyanate foam. The
support construction 56 is not, however, limited to foam materials. In
other embodiments the support construction 56 can take the form of two
phase materials, plastic powder, carbon powder, and others. Furthermore,
non-porous materials could also be used. The support composition 56 can
be air curable (not thermal) foam or other (air curable) sacrificial
material. The support composition 56, therefore, can be cured using any
variety of techniques. In short, many different types of materials and/or
compositions and/or structures in addition to those disclosed herein can
be used to provide support of the article 50 during at least a portion of
the thermal processing.

[0018]During the thermal processing of the article 50 as it becomes a
hardened article the support composition 56 is sacrificed according to
its material and/or composition and/or structure. For example, the
support composition 56 can thermally decompose during the temperature
processing. In one form the support composition 56 supports the article
50 during burn-out and thereafter eventually decomposes under further
temperature processing, where the further temperature processing includes
the remaining processing prior to the article becoming hardened or after
the article has become hardened. The same is true whether the support
composition 56 is sacrificed through any other sacrificial action.

[0019]In some forms the support composition 56 can have sufficient
permeability to allow evolving gases to readily pass while providing
sufficient strength to hold a desired geometry of the article 50 intact.
Furthermore, the support composition 56 can evolve, during the
temperature processing, into a fairly rigid relatively cellular
carbonaceous structure. In some forms the support composition 56 can be
rigid prior to the beginning of thermal processing. Some forms of the
support composition 56 can eventually oxidize into a gas, but some forms
can also evaporate or melt, among other types of changes. The support
composition 56 can be removed from the article 50 through any number of
actions during or after the thermal processing. To set forth just a few
non-limiting examples, the support composition 56, or its byproducts as a
result of the sacrificial action, can be poured, dumped, suctioned, or
blown from the article 50. Other techniques of removing the sacrificial
composition 56 are contemplated herein.

[0020]Turning now to FIG. 3, one embodiment of article 50 and support
composition 56 is shown. Portions 58 and 60 of the article 50 are shown
on either side of the support composition 56. Such a configuration may be
present as between a shell and a core of the article 50, however the
portions 58 and 60 can represent any variety of structural features of
the article 50, whether or not the portions 58 and 60 represent different
features or similar features. The support composition 56, though shown
having a relatively constant cross section along the length of the
portion depicted, can have any variety of shapes and sizes in other
applications. For example, the support composition 56 can have a cross
sectional area that varies along the length between the portions 58 and
60. Furthermore, the support composition can be placed between portions
58 and 60 that change direction in addition to relative sizing.

[0021]In one form the present application provides an apparatus comprising
a ceramic mold article capable of being thermally processed from a
pre-fired shape to a fired-shape to produce a fired ceramic mold, and a
sacrificial structural material coupled with the ceramic mold article to
stabilize the orientation of the ceramic mold article, the sacrificial
material dispersible when the ceramic mold article is thermally
processed.

[0022]In another form the present application provides an apparatus
comprising a free-form fabricated mold having a binder matrix capable of
being burned out to form a fired ceramic mold, and a supporting material
coupled with and at least partially removable from the free-form
fabricated mold prior to producing a completed fired ceramic mold, the
supporting material structured to encourage the free-form fabricated mold
to maintain its shape at least during some portion between the starting
temperature and processed temperature.

[0023]In still another form the present application provides an apparatus
comprising a shaped mold article having a ceramic particle and binder
matrix composition, the shaped mold article operable to be processed from
a first state to the second state, the second state characterized by a
loss of at least a portion of the binder matrix, and means for
sacrificially supporting the shaped mold article during processing from
the first state to the second state.

[0024]In yet another form the present application provides a method
comprising forming a ceramic article having ceramic particles, filling a
space in the ceramic article with a sacrificial support material,
subjecting the ceramic article to a temperature process for hardening the
ceramic article, and removing the sacrificial support material during the
temperature process.

[0025]While the invention has been illustrated and described in detail in
the drawings and foregoing description, the same is to be considered as
illustrative and not restrictive in character, it being understood that
only the preferred embodiments have been shown and described and that all
changes and modifications that come within the spirit of the inventions
are desired to be protected. It should be understood that while the use
of words such as preferable, preferably, preferred or more preferred
utilized in the description above indicate that the feature so described
may be more desirable, it nonetheless may not be necessary and
embodiments lacking the same may be contemplated as within the scope of
the invention, the scope being defined by the claims that follow. In
reading the claims, it is intended that when words such as "a," "an," "at
least one," or "at least one portion" are used there is no intention to
limit the claim to only one item unless specifically stated to the
contrary in the claim. When the language "at least a portion" and/or "a
portion" is used the item can include a portion and/or the entire item
unless specifically stated to the contrary.